Adjustable ring gauge



March 1952 e. HOHWART ET AL ADJUSTABLE RING GAUGE Filed July 26, 1946 Patented Mar. 4, 1952 ADJUSTABLE RING GAUGE George Hohwart and Ernest F. Hohwart, Detroit, Mich., assignors to N. A. Woodworth Company, Ferndale, Mich., a corporation of Michigan Application July 26, 1946, Serial No. 686,493

13 Claims. (01. 33-199) I This invention relates broadly to new and useful improvements in radially adjustable devices such as ring gages and journal bearings and more particularly to a device of this type that will maintain substantially exact circularity throughout a range of adjustment.

Although not limited thereto, the concept of this invention is primarily adapted and preeminently suited for adjustable ring gages.

Ring gages of the conventional AGD type have been unsatisfactory in that they tend to assume a generally triangular shape when adjusted from a normal position; consequently the adjusted gage contacts the work at only three points. As a result of this phenomenon, the gage is worn relatively rapidly and unevenly and must be discarded much sooner than if true circularity could be maintained.

In the past, several solutions to the problem have been advanced, but all have been unsatisfactory for one reason or another. Perhaps the most satisfactory solution heretofore suggestedis shown in our copending application Serial No. 653,571 which was filed March 11, 1946. This application discloses a thread ring gage having inner and outer split ring members. The inner edge of each member is'ecc'entric to the outer edge thereof and the members are arranged in diametrically opposed relation so that the thinnest portion of one is adjacent to the thickest'portion of the other. Means is provided for contracting the outer member against the inner member and for expanding the inner member against the outer member. However, although this construction maintains true circularity of the gage opening throughout a range of adjustment, the eccentric formation of the members makes them difficult to machine and increases manufacturing costs.

We have now discovered a construction which permits the split ring members to be formed with concentric inner and outer edges and at the same time maintains substantially true circularity of the gage opening at all times. As a result, the gage can be manufactured easier, quicker, and less expensively than heretofore.

In the'drau' ingforming a part of this specification and wherein. like numerals are employed to designate like parts throughout the same,

Fig. 1 is a plan view of a thread ring gage embodying the inventive concept of this invention. Fig. 2 is an edgewise elevational view thereof, and Fig. 3 is an enlarged fragmentary, vertical sectional view taken .onthe line 3-3 of Fig. .2.

The present invention is adaptable for use either as a plain ring gage or a thread ring gage, the latter being shown by way of illustration. In the drawing which shows a preferred embodiment of the invention, the insert is designated by the numeral [0 and the body by the numeral l2. Both the insert and the body are generally circular in shape as shown in Fig. l and are relatively thick as shown in Fig. 2. The insert l0 may be made of hardened steel or other suitable or conventional material of the type commonly employed for gaging elements. The body l2 may be made. of any suitable material, but preferably from a light metal such as aluminum. When thus constructed, the gage is 50% lighter in weight than the standard AGD gage. important in a device of this character, since the reduced weight results in less fatigue and assures a more sensitive feel.

As best shown in Fig. 1, the insert l 0 has a generally cylindrical peripheral surface l4 and is provided with a concentrically located internally screw-threaded opening l6 which is adapted to receive and snugly fit an externally screwthreaded workpiece. In accordance with practices well known in the art, the opening I6 may be provided with threads of any suitable type or I size depending on the character of the particular work to be tested. Extending radially through the insert at any suitable point along its circum-' ference' is a through slot 18 which permits a radial expansion and contraction of the same.

The body I2 also has a generally cylindrical peripheral surface 20 and is provided with a concentrically located opening 22 which receives and snugly fits the cylindrical periphery of insert 10. At any suitable point along its circumference the body I2 is provided with a radial through slot 24 which permits it to be radially expanded and contracted.

By reason of the fact that both the insert l0 and the body l2 have concentric inner and outer edges they can be formed easily and quickly by conventional machine tools and without the need of special jigs or the like; and, since the insert and body are the main elements of the gage, production costs are considerably less than for the ring gage disclosed in our copending application hereinabove referred to.

In operation of the gage, the body l2 acts in the manner of a hose clamp to apply contracting forces radially against the insert I0. Manifestly, radial adjustment of the insert and body can be achieved only by deforming or flexing the mate This isrial from which they are made. When split ring members such as the insert l and body l2 are flexed to expand or contract them, they tend to elongate so that the gage opening assumes an oval shape. Elongation occurs along a plane through the adjusting slot or parallel to and between the ends of the ring.

According to the present invention the tendency of insert I0 to elongate is overcome or compensated by positioning it in the body l2 with adjusting slot IS in diametrically opposed relation to adjusting slot 24 and by providing the body with radial slots 26 at points behind but adjacent to its ends. It will be observed that slots 28 extend only part way through the body l2 and that they open outwardly onto its periphery. Slots 26 preferably are provided at their inner ends with terminal holes 28 which increase the flexibility of the body at these points and eliminate corners or other sharp or irregular features where fractures might occur when the body is under stress. As a result of this construction the body I2 is more or less uniformly rigid throughout its circumference except for the portions 30 disposed radially inwardly from terminal holes 28. These portions offer markedly less resistance to radial adjustment or deformation of the body 12. When body I2 is tightened against the insert by pulling its ends toward each other, the two sections between slot 24 and slots 26 in effect pivot at portions 30. In other words, the body portions designated at in effect form flexible hinges connecting the terminal portions of the body to the rest of the body. As a result, these sections cause considerably greater pressureto be exerted against the rear portion of the insert (viz., the portion directly opposite the adjusting slot l8) than is exerted against the front portions thereof (viz., the portions adjacent to adjusting slot l8). Application of force against the insert H] in this manner compensates any tendency for the latter to elongate during adjustment.

Any suitable means for tightening the body l2 against the insert l0 can be employed, but we prefer to use a clamp screw 32 which is disposed in aligning openings 34 and 36 and extends transversely across adjusting slot 24. In order that no part of the screw projects from the body I2 and to provide a radial shoulder for the screw head, the latter is recessed in a counterbore 38 at the outer end of opening 34. Opening 36 is internally screw-threaded to engage the external threads of screw 32. Manifestly, tightening of screw 32 tends to draw the ends of body !2 together and to pull the same tightly against the insert H) in the manner hereinabove described. Conversely, loosening of screw 32 permits the inherent resiliency of the insert and body to expand them.

According to the present invention the insert [0 and body [2 can be expanded beyond their normal positions by an adjusting screw 40 which is disposed in an internally screw-threaded radially extending opening 42 provided in the body [2. As best shown in Fig. 1, the opening 42 is positioned in alignment with the adjusting slot 18 and, as shown in Fig. 3, the screw 40 is provided at its inner end with longitudinal extension or nose 44 which enters the slot I8 and seats against the radially inwardly tapered walls thereof. Nose 44 preferably engages the walls of slot l8 substantially behind the periphery of insert I0; and, since the angle of the walls changes with each adjustment, the contacting portion of the nose is rounded as at 46 to assure a uniform contact in all adjusted positions of the gage. Manifestly, when the screw 40 is tightened, it expands the insert 10 solidly against the body l2.

Also, it is contemplated that, in the case of ring gages, the side walls of adjusting slot [8 be provided with centrally located confronting recesses 48 and 50, each of which has angularly related, coined bearing surfaces which engage nose 44 in such manner that the ends of the insert are held in fixed relation. Moreover, it is further contemplated that in the case of thread ring gages, the bearing surfaces be arranged in such angular relation to a diametric plane through the screw 40 that the ends of the insert 10 are flexed axially in opposite directions to compensate for offset produced in the threads at opposite sides of adjusting slot 18 when the gage is adjusted radially from its normal position. This may be done conveniently in the manner disclosed in our copending application hereinabove referred to.

To adjust the gage,'the usual procedure is to loosen clamp screw 32 and then insert a master thread gage set plug (not shown) into the opening 16. If necessary, opening l6 can be expanded from its normal position to permit ready insertion of the set plug by tightening the adjusting screw 40. In any event, the adjusting screw 40 is positioned so that there is precisely the de sired amount of frictional resistance between the wall of opening 16 and the set plug when clamp screw 32 is tightened. The latter operation contracts the body to impose radially contracting forces on the insert, and the amount the latter is contracted is limited by nose 44. Furthermore, the compressive forces are imposed in such manman that any tendency of the insert to elongate is compensated or corrected, and the opening I3 is maintained in substantially exact circularity throughout the entire range of adjustment. The set plug is then removed and the gage is properly adjusted for use.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the size, shape, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

Having thus described the invention, we claim:

1. A thread ring gage comprising an internally threaded annular insert having an adjusting slotextending radially therethrough and defining spaced ends, said insert characterized by a tendency to become eccentric when adjusted; an annular body around and snugly fitting said insert having a radial through slot defining spaced end portions disposed substantially in diametrically opposed relation to said adjusting slot and adapted to apply a radially contracting force against the insert; a clamp screw adapted to pull the ends of said body toward each other and regulate the amount of force exerted by the bodyagainst the insert, said insert and said body each having concentric inner and outer edges, said body provided with radial slots, which extend part way therethrough, open onto the periphery thereof and are located in generally equispaced relation on opposite sides of said through slot and in the first quadrants of the body adjacent the through slot.

2. In a thread ring gage, an internally threaded annular insert having an adjusting slot extending radially therethrough and defining spaced ends, said insert characterized by a tendency to become eccentric when adjusted; an annular body around and snugly fitting said insert having a radial through slot defining spaced end portions disposed substantially in diametrically opposed relation to said adjusting slot and adapted to apply a radially contracting force against the insert, said insert and said body each having concentric inner and outer edges and said body provided with radial slots which extend part way therethrough and open onto the periphery thereof, said last-mentioned slots located at opposite sides of the ends of said body and each spaced approximately 70 from said ends.

3-. A thread ring gage comprising an internally threaded annular insert having an adjusting slot extending radiall therethrough and defining spaced ends, said insert characterized by a tendency to become eccentricwhen adjusted; a body around and snugly fitting said insert adapted to apply a radially contracting force'ag'ainst the same, said body formed with a radial through slot substantially in diametrically opposed relation to the ends of said insert and also provided with radial slots which extend part way therethrough and open onto the periphery thereof, said latter slots located at' points along the periphery of said outer member at opposite sides of a diametrical plane through the adjustingslot and inthe first quadrants of the outer member adjacent the adjusting slot of said insert; means acting upon the body to close said radial through slot and. to draw said body tightly against said insert; and an adjusting member carried by the body positioned to enter said adjusting slot, the walls of said slot having bearing surfaces positioned for engagement with the adjusting member on opposite sides of the latter and said bearing surfaces so constructed and arranged that tightening of the adjusting member thereagainst moves the ends of said insert in opposite directions to compensate for offset produced in said internal threads at opposite sides of the adjusting slot due to radial adjustment of the insert.

4. A thread ring gage comprising an internally threaded annular insert having an adjusting slot extending radially therethrough and defining spaced ends, said insert characterized by a tendency to become eccentric when adjusted; a body around and snugly fitting said insert adapted to apply a radially contracting force against the same, said body formed with a radial through slot in diametrically opposed relation to the ends of said insert and provided in the first quadrants of the body at opposite sides of said through slot with radial slots which extend part way therethrough and open onto the periphery thereof; and an adjusting member carried by the body positioned to enter said adjusting slot, the walls of said slot having bearing surfaces positioned to engage the adjusting member on opposite sides of the latter and said bearing surfaces so con,- structed and arranged that tightening of said adjusting member against said bearing surfaces moves the ends of aid insert in opposite direce tions to compensate for oiiset produced in said internal threads at opposite sides of the adjusting slot due to radial adjustment of the insert.

5. A thread ring gage comprising an annular radially adjustable, internally threaded insert having a radial through slot defining spaced ends; an annular body fitting snugly around said insert provided With a radial through slot for radial adjustment; means for radially adjusting said insert and said body,

said insert characterized by a tendency to become eccentric when adjusted and said body provided in the first quadrants'adjacent the radial through slot of the body with radial slots which extend part way therethrough and open onto the periphery thereof, said slots located at points along the circumference of said body adjacent to a portion of said insert which elongates when the same is adjusted; and means carried by the body coactive with said insert duning radial adjustment thereof to compensate automatically for axial offset produced in the threads when the gage is adjusted.

6. A thread ring gage comprising an annular radially adjustable, internally threaded annular insert having a radial through slot defining spaced ends and characterized by a tendency to become eccentric when adjusted; an annular body fitting snugly around said insert provided with a radial through slot for radial adjustment and adapted to apply a radially contracting force against the insert, said body formed in the first quadrants adjacent the radial through slot of the body'with radial slots which extend part way therethrough and open onto the periphery thereof.

7. A ring gage comprising an annular radially adjustable insert having a radial through slot defining spaced ends; a radially adjustable annular body around and snugly fitting said insert; said insert characterized by a tendency to become eccentric when adjusted, said body having 'a radial through slot defining spaced ends and provided in the first quadrants adjacent the radial through slot of the body with radial slots which extend part way therethrough and open onto the periphery thereof, and means for radially adjusting said insert and said body.

8. A device of the character described comprising concentric and radially adjustable inner and outer radially slit ring members characterized by a tendency to become eccentric when adjusted, each member having end portions at opposite sides of its radial slit and said members arranged with the end portions thereof in diametrically opposed relation and said outer member having radial slots in the first quadrants of the member adjacent the ends thereof, which slots extend part way through said outer member and open onto its periphery; a clamp screw carried by the outer member, said screw connecting the ends of said outer member and operative to draw them toward each other and to pull the outer member solidly against said inner member; and an adjusting screw carried by said outer member positioned to seat against the ends of said inner member and operative when tightened thereagainst to expand said inner member radially outwardly against the outer member.

9. A device of the character described comprising concentric and radially adjustable inner and outer radially split ring members characterized by a tendency to become eccentric when adjusted, said members arranged with the end portions thereof in diametrically opposed relation and said outer member having radial slots in the first quadrants adjacent the ends thereof, which slots extend part way through said outer member and open onto its periphery; and a clamp screw carried by the outer member, said screw connecting the ends of said outer member and operative to draw them toward each other and to pull the outer member solidly against said inner member.

10. A device of the character described comprising concentric and radially adjustable inner and outer radially split ring members characterized by a tendency to become eccentric when adjusted, said members arranged with the end portions thereof in diametrically opposed relation and said outer member having radial slots, each spaced circumferentially approximately 70 from its ends, which slots extend part way through said outer member and open onto its periphery; an adjusting screw carried by said outer member positioned to seat against the ends of said inner member and operative when tightened thereagainst to expand; said inner member radially outwardly against the outer member, the relatively thin portions disposed radially inwardly from said slots in effect defining hinge means; and means for drawing the sections of said outer member disposed between its ends and said slots toward each other and against said inner member.

11. In a device of the characterdescribed, radially adjustable inner and outer radially split ring members characterized by a tendency to become eccentric when adjusted, said members having concentric inner and outer edges and arranged with their ends substantially in diametrically opposed relation, said outer member having radial slots which extend part way therethrough and open onto the periphery thereof, said slots being in the first quadrants of the outer member adjacent the ends thereof and spaced substantially equidistantly from respective of said ends.

12. In a device of the character described, snugly interfitting inner and outer radially split ring members characterized by a tendency to elongate when adjusted and arranged with their ends substantially in diametrically opposed relation; and means for flexing said members to obtain such adjustment, said outer member formed in the quadrants thereof adjacent to its ends with radial slots which extend inwardly from its periphery and part way therethrough.

13. In a device of the character described, annular inner and outer members, each having a radial through slot for radial adjustment and each characterized by a tendency to elongate when adjusted, both of said members being relatively stifi to resist adjustment and said outer member having hinged terminal portions; and means for drawing said terminal portions toward each other.

GEORGE HOHWART. ERNEST F. HOHWART.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

